|GARCIA, MARIA CRUZ - Institute Of Castilla - Spain|
Submitted to: ASABE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: 5/28/2014
Publication Date: 7/13/2014
Citation: Garcia, M., Vanotti, M.B. 2014. Nitrogen recovery from liquid manure using gas-permeable membranes: Effect of wastewater strength and pH control. Proceedings of American Society of Agricultural and Biological Engineers Annual International Meeting. p. 1-6.
Technical Abstract: The costs of fertilizers have rapidly increased in recent years, especially nitrogen (N) fertilizer such as anhydrous ammonia which is made from natural gas. Thus, new treatment technologies for abatement of ammonia emissions in livestock operations are being focused on N recovery in addition to the N removal. Nitrogen recovery from swine manure was investigated using a new technology that uses gas-permeable membranes at low pressure. Membrane manifolds are submerged in the manure and the ammonia is removed from the liquid before it escapes into the air. Bench experiments were conducted using raw liquid swine manure collected from manure pits in nursery, finishing and sow barns. This provided manures of various strengths (low, medium and high) with ammonia concentrations ranging from 1070 to 2290 milligrams per liter and total solids concentrations from 8.6 to 24.9 grams per liter. As ammonia content increased in manure, more N was captured by the process. The process was optimized by controlling the pH. With no pH adjustment, ammonia recovery from manure was 55 percent (%). When pH of manure was adjusted, the process recovered, in a concentrated form, more than 80% of the ammonia contained in the raw manure. The volatile solids did not pass through the gas-permeable membrane. These results suggested that the new technology is useful for recovering and concentrating the ammonia contained in raw swine manure, reducing environmental pollution potential while converting ammonia into a valuable plant fertilizer.